Thyroidectomy and Subtotal Thyroidectomy

THYROIDECTOMY Thyroidectomy is the surgical removal of thyroid gland while preserving the parathyroid gland. Relevant anatomy: The thyroid gland is a highly vascular organ situated in front and sides of the lower part of the neck opposite to the 5th, 6th, 7th and 1st thoracic vertebra. → By the pretracheal layer of the deep cervical fascia. → Consists right and left lobe connected by isthmus. → Lobes are lonical. Relations with the lobes: Lateral surface: Sternohyoid. Superficially: sternohyoid, scip belly of omohyoid overlapped below by the anterior border of the sternomastoid. Medial surface: Lies over the larynx & trachea. At the upper part: external laryngeal nerve passes deep to this surface on its way to 'cricothyroid'. At the lower part: the recurrent laryngeal nerve lies below trachea & esophagus. Posterolateral surface: In relation ship with carotid sheath posterior border is related to inferior thyroid artery and anastomosing branch of the superior thyroid artery. Parathyroid glands are related to the posterior border. Isthmus: Lies in front of the 2nd and 3rd rings of the trachea. Relation: - Pre tracheal fascia - Sternothyroid - Sternohyoid - Ant jugular vein Indication for thyroidectomy: 1) Diffuse simple goitre: physiological goitre during pregnancy and puberty on iodine deficiency. If established goitre - cosmetic surgery/ decompression is required. 2) Diffuse colloid goitre: For cosmetic reason. Surgical decompression (trachea, esophagus, recurrent laryngeal nerve). Prevention of complication such as secondary thyrotoxicosis, malignancy or sudden hemorrhage leading to choking of the air ways. It retro sternal extension is rare. 3) Simple nodular goitre: Risk of malignancy or secondary thyrotoxicosis. Contraindication (may not be indicated for surgery): women of older age group, especially in the goitrous districts having a nodular goitre for a longer period. Solitary or discrete thyroid nodular (COLD NODULES): solitary growing single discrete separate distance incidence of malignancy is high. SUBTOTAL THYROIDECTOMY Pre-operative investigation: 1) Laryngoscopy: to see the vocal cord position and to exclude any asymptomatic cord paralyzed. 2) X-ray of enlarged goitre to see any deviation or kinking of trachea. 3) Thyroid nodule scan to exclude any autonomous nodule or toxic intervening thyroid tissue to calculate the amount of tissue to be removed. Pre-medication: Morphine or path along with hyoscine may be given as the pt are rather emotional. Tracheal intubation: Position of the patient: The neck of the patient is extended by a pillow below the shoulder. Incision: A curved incision is made about 1 inch above the inner ends of the clavicle and entending from the lateral border of the sternocleidomastoid to the corresponding point on the other skin. Skin and superficial fascia are incised. ↓ Platysma is divided at a slightly higher level no produce a fine scar. ↓ Upper flap reflected upwards to the level of thyroid cartilage. ↓ Lower flap is reflected downwards to the sternum. ↓ Exposure of the goitre. Deep fascia is incised vertically in the mid line. ↓ Intrahyoid muscles are referred, sometimes may be divided, veins are divided in b/w ligament. ↓ Pretracheal fascia is incised & a finger, as is known, the whole to extend of the goitre. Ligature of blood vessels: divided in b/w ligatures = superior thyroid vessels (artery), middle, inferior) Resection of the goitre and controlling bleeding. Closure: Intra hyoid muscles repaired by interrupted sutures. ↓ Deep fascia & the muscles are approximated by one two. ↓ A drainage is inserted - tyne ↓ platysma sutured separated ↓ skin closed either by a silk or by nylon suturing or Mitchel's clips or even steric strips for cosmetic purpose. Post-operative: Haemorrhage → dyspnea Thyroid crisis → tachycardia Pyrexia (105°F), restlessness, delirium Prevention: 1 - preoperative Rx on thyroid state 2 - IV glucose + potassium to control tachycardia Propranonol, digoxin for atrial fibrillation IV lugol's iodine. 3 - recurrent laryngeal nerve paralysis due to poor the nerve by edema or hematoma undue stretching.